1. Field of the Invention
The invention relates to a door made of plastic material for motor vehicles, with a stiffening suitable for receiving the outer and inner shells of the door, said stiffening transmitting the forces occurring into the frame of the body of the vehicle.
2. Description of the Prior Art
Indisputably, the side door is a highly complicated component of the body of a motor vehicle. The door has to have exceptionally high strength and is expected to function even after a collision accident.
Generally, a door made of steel sheet satisfies said requirements. Efforts made to reduce the weight have resulted in door designs comprising a plastic outer shell of the door and a plastic inner shell of the door applied to a stiffening construction consisting of steel profiles or sections. The forces acting on such a construction are transmitted into the frame of the auto body by the stiffening construction consisting of steel sections. With a known design, the outer and inner shells are manufactured by deep-drawing and combined with each other.
Said doors represent a combination of different materials; however, such doors do not meet the requirements in automobile construction particularly with respect to safety.
Now, the present invention is based on the problem of further reducing the weight of a plastic door for motor vehicles and to construct such a door in such a way that it will fully satisfy all requirements without a stiffening construction made of steel sections while still having substantial safety reserves.